Preparation of magnesium oxysulfate cement using magnesium-rich byproducts from the production of lithium carbonate from salt lakes

Low-cost magnesium oxysulfate (MOS) cement was prepared using magnesia derived from the calcination of magnesium-residue from the production of LiCO3 from salt lake brine. Setting time, mechanical strength, hydration mechanism, hydration products and microstructure of this MOS cement were determined. MOS cement prepared with magnesia after calcination at low temperatures and high molar ratio of a-MgO/MgSO4 was found to harden rapidly but the later-stage strength decreased. However, partial replacement of magnesia obtained from the calcination of magnesium-rich residues by pure light burned magnesia and addition of 5·1·7 phase seed crystals are viable strategies for obtaining MOS cement with improved properties.